I learned the hard way that on a cruise you should turn your mobile device off or put it in airplane mode no matter who your carrier is. That’s because I woke up one morning to text messages reading, “Welcome to Iceland” then “Welcome to France” (which is where we were) and then when I returned home I had accrued over $380 in roaming fees without even using my phone. Ouch!

Luckily, I called T-Mobile and they credited my account but it could’ve been because I had an awesome agent. Turn your phone off or put it in airplane mode as soon as you leave port to prevent this from happening.

Tried this tip? Let me know in the comments!Have your own tip? Email it to whitney@johnnyjet.com!Want to see more tips?Click here for all 189!

Want even more travel tips? Subscribe to the Daily Travel Tip newsletter! All you have to do is sign up for the weekly newsletter by filling in your email address and checking the Daily Travel Tip box in the top-right corner of the homepage.

If you already subscribe to the newsletter, fill in your email and check the Daily Travel Tip box in the same top-right corner of the homepageand you’ll receive an email with a link to update your JohnnyJet.com preferences. On that page, just click the Daily Travel Tip box and Update Profile and you’ll have Johnny’s best tips, straight to your inbox each day. And don’t worry—it’s easier than it sounds!

I found this out the hard way! Maritime Data is NOT included in international packages. AT&T was pretty cool about it and reversed all of my charges, otherwise, it was going to be a very large and unexpected bill.

I am surprised, with all your traveling, you are not swapping out a domestic SIM card with an international one when out of country. Also, it is the data use that silently and automatically runs in the background. Go into cellular settings and turn off data use so it will be restricted to wifi only.